Dead Roland SH09

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Dead Roland SH09

Postby magnus » Tue Dec 01, 2009 9:55 pm

Hi all,
I'm wondering if anyone has experienced a problem like mine, or if anyone has any suggestions as to what I should do next.
My SH09 died suddenly last night - it was playing normally, then without warning everything stopped, as if the plug had been pulled. No smoke, no funny smells, no blinking LEDs. The case was open as I'd been looking inside for the cause of another, long standing fault (external input doesn't work - possibly a dead opamp), but I didn't pour coke on the circuit board or anything, so I don't think this was the cause.
I think I read somewhere that the power supplies of these synths can get quite unreliable at this age, so I'm wondering if this is the cause. Any suggestions as to how I might proceed?

cheers
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Re: Dead Roland SH09

Postby computron » Tue Dec 01, 2009 10:21 pm

testing is needed to find the fault but it does sound like a power supply issue
here is a link with a board layout
http://www.cykong.com/Synths/Roland%20S ... ndSH09.htm
The service notes are very good!
if you have some expereince you can trace the fault yourself to repair ,This is a pretty easy board to work on. If your unconfortable a tech is recomended.
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Re: Dead Roland SH09

Postby blanik » Wed Dec 02, 2009 12:50 am

really sounds like a power supply problem, the main power first goes through the switch and a fuse (might be the culprit) then to the transfo, which take the wall voltage and lowers it to 25V / Ground / 25V at the "power supply PCB" input, it then might go through either two fuses (UK and Europe models) or two metal jumpers then to the transistors, caps and 16 pin IC (power regulator), the IC regulates the power to a precise +15V / Ground / -15V (at the right side of the power PCB, the wires are doubles, two +15V, two grounds and two -15V) measure voltages there, if you have bot 15Volts then your problem is elsewhere, but no LED working screams a power supply problem...
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Re: Dead Roland SH09

Postby magnus » Wed Dec 02, 2009 9:50 pm

Thanks for your help - it was the power supply - one of the fuses inside had blown.
cheers
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Re: Dead Roland SH09

Postby blanik » Wed Dec 02, 2009 11:36 pm

you removed your question about the Ext Signal slider??

did you find the trouble?
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Re: Dead Roland SH09

Postby magnus » Thu Dec 03, 2009 1:00 am

Er sort of... I should have looked at the schematics more carefully. There was a diagram at the bottom showing where IC11 is. Not all good news though - the guy that told me it was probably IC11 said it was a 4558, but the schematics actually suggest it is a BA662 (as rare as rocking horse poo). I think I'll buy an equivalent IC and see if that improves matters, unless anyone has any better ideas. Just to restate the problem - the external input is faint when the slider is set to maximum or minimum, and even fainter in between
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Re: Dead Roland SH09

Postby blanik » Thu Dec 03, 2009 1:36 am

i don't think IC 11 has something to do with the problem, it looks more like Q32 and Q33 driving the input of the EXT line (if IC 11 had a problem you'd probably also have problems with the VCO and SUB sliders), but if one of the transistors was bad then nothing would come out, not even a faint signal, my feeling is that the problem lies in the slider itself or the EXT input jack PCB, i have a SH-09 and when i got it a ground copper trace had lifted from the PCB, i guess i'm not the only one who can have this problem, so i would start with those places
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Re: Dead Roland SH09

Postby magnus » Mon Dec 07, 2009 10:47 pm

Okay, I've tried the PCB connected to the input - no luck. Looks like I'm going to have to muster up the courage to replace the slider. Thanks for helping out
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Re: Dead Roland SH09

Postby blanik » Tue Dec 08, 2009 5:21 am

before you dismantle the slider, make sure the part of the slider that's supposed to be grounded is actually grounded (check with a meter) might be a bad ground (or a part that shouldn't be grounded)
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